The present invention is related to a digital broadcast multiplexing and sending apparatus designed for mobile appliances.
As to synchronizing methods for a plurality of streams, the below-mentioned techniques are known.
JP-A-2005-277464 has disclosed such a broadcast material signal switching apparatus that while a broadcast material signal transmitted from a mother station is switched to a broadcast material signal of a net-receiving station, a net queue detector detects a net queue signal contained in the broadcast material signal transmitted from the mother station; and since switching precision of a selection switch is increased, the switching operation between the broadcast material signals is performed in a smooth manner, while partial viewing of the broadcast material from the mother station is not produced in the transmitted signal.
In another conventional technique described in JP-A-2001-257654, in order that an STC (System Time Clock) value measured by a switching device is synchronized with an STC value measured by an encoder when a system is switched, a synchronous generation controller notifies a reference STC value to the switching device and the encoder respectively by utilizing an ancillary signal packet contained in an SDI (Serial Digital Interface) signal. Then, the encoder which has received the SDI signal performs compressing/encoding operations with respect to a picture signal in such a manner that frame phases between the systems are matched with each other based upon this reception result so as to convert the compressed/encoded picture signal into a bit stream, and also, extracts the reference STC value from the ancillary signal packet of the SDI signal. Then, the encoder replaces measurement STC values measured at the respective STCs by reference STC values, and adds the reference STC value to each frame of the bit stream to be transmitted. Also, the switching device which has received the SDI signal switches the systems based upon the reference STC values extracted from the ancillary signal packet.
JP-A-2003-101976 has realized such a stream producing apparatus capable of accepting a change in program numbers in a flexible manner by employing a temporal information correcting unit. The temporal information correcting unit calculates a correction value equivalent to such a time required in a signal processing operation by a signal processing unit, and then, corrects a value of a PCR (Program Clock Reference) contained in a stream which is changed during the signal processing operation.
Also, JP-A-2001-28738 has disclosed such a synchronizing method for synchronizing streams with each other by employing an externally-generated reference clock.